Discharge-screen for centrifugal grinding-mills.



J. F. DIETRICH.

DISCHARGE SCREEN FOR GENTRIFUGAL GRINDING MILLS.

APPLICATION FILED AUG. 26, 1912.

1,058,416. Patented Apr. 8, 1913.

W! III/E8858:

. I/wmmR imam F D15 TRIO] UNITED STATES PATENT OFFICE.

JOSEPH F. 'mn'rmcn, or GOLD HILL, NEVADA, AssINon 'rorAUL HAHNEWALD, or

- I AVON, COLORADO.

DISCHARGE-SCREEN ron cENTRInUoAf. GRINDING-MILLS.

Specification of Letters Patent.

Application filed August 26, 1912. Serial No. 717,006.

Patented Apr. 8, 1913.

To all whom itmay concern Be it known that I, J OSEPH F. DIETRICH, a citizen of the United States, residingat Gold Hill, in the county of Storey and State of Nevada, have invented a new and useful Discharge- Screen for Centrifugal Grinding-Mills, of whichthe following is a' specification in such full and clear terms as will enable those skilled in the art to con-i struct and use the same. I

This invention relates to a screen for r0- tary grinding mills, and its object is to provide a mill with-more efficient discharge of rather than to discharge radially through the mill screens, the total screen area being comparatively less when considered with respect to'materials circulating around the 7 screen than would be the case if the .-ma-

terials impinged directly thereupon at an angle of 90..

In this mill the screen is placed substan- .tially radially to the body of the mill so that as the rolls cause the pulp to circulate around the mill it strikes the screens substantially at right angles thereto, thus effecting a greater discharge with a given screen area than is possible where the screens are placed circumferentially.

In the drawings in which the same numeral of reference is applied to the same portion throughout the several views, Figure 1 is a vertical sectional view through the mill having this screen applied thereto, Fig. 2 is a plan view of the mill, and Fig. 3 is a sectional view showing the screen and discharge trough of the mill.

The numeral 1 represents a suitable fixed base plate which has a trough 2 at the edge upwardly from the base plate is a suitable hollow support 4 upon which is revolubly mounted a frame 5. The. frame 5 rotates upon a suitable bearing upon the hollow a bevel gear 10, said bevel circumferential screens for.

support and the rollers 6 are provided with short shafts 7 which rotate within journal boxes on the frame 5. Above the frame 5 the hollow support is provided with a suit able collar 9 upon-which collar is supported gear having a suitable connection 11 with the frame 5 for turningthe rollers.

Above the bevel gear there is a suitable support 11 having journal boxes 12 and 13 which support a shaft 15, said shaft having a small gear 16 in mesh with the large bevel gear.

The ore is fed into the mill through the hollow support by means of a suitable pipe 17. Above the base of the mill there is a suitably high cylindrical wall 19 to prevent the rolls from splashing the pulp over the top thereof. The baseor pan upon which the track die is mounted has three walls 20, which. extend spirally away from the track die and terminate at screens 21. there being three of said screens, each of which is placed substantially radially with respect to the track die. As the material is pulverized by the mill it is carried around and impinges substantially at 90 tothe screens, thus effecting the greatest possible discharge of pulverized material and any to be again operated upon by the next roll in turn.

The result of the foregoing construction is that the pulp passes around the mill in several Waves, each of which waves is in turn brought to a full stop and compelled to start over again, thus efiecting the maximum discharge of pulp through the screens.

. Itwill be understood by those skilled in the art that while the mill shown is of the Chilian mill type, that these screens may be 'radially extending screens. and substantially spiral walls leading to said screens from said pan, substantially as described.

- 2. In a' grinding mill, a grinding pan, In testimony whereof I have hereunto set 1 means therein to pulverize the ore placed in my hand this 9" day of October, A. D. 1912, said pan, a plurality. of screens extending in the presence of two subscribed witnesses.

radially around the pan, and a plurality of JOSEPH F. DIETRICH. 5 substantiallyspiral walls leading from the Witnesses:

pan to said screens, substantially as de- O. P. GRIFFIN,

scribed. A. H. KEPHART. 

